Through-Hole Trimming Potentiometer Design Kit - Trimpot® H-870 Bourns Trimpot® H-870 Trimming Potentiometer design kit to accommodate various applications and board designs. Each H-870 Design kit contains a variety of sizes of multiturn and single-turn through-hole potentiometers which have an open frame and are sealed. The H-870 series Design Kits have a wide variety of applications including Phone headsets, Power supplies, Credit card readers, Smoke detectors, Plasma televisions, GPS navigation, Barcode scanners, CCTV cameras, Control systems, Radar systems, Analytical equipment and Stereo equipment